1. Field of the Invention
The present invention relates generally to a switch knob having an indicator portion which is illuminated with light from a light source on the main body portion of the switch and, in particular, to an improved switch knob in which a light transmissive cam system is insertion molded into an operation portion of the switch knob.
2. Description of the Related Art
A conventional switch knob with a light is disclosed in Japanese Laid Open Patent Publication No. Sho 61-161843. The conventional switch knob has an illuminated portion lit by a light source such that the light from the light source is directed to the illuminated portion of the operation knob by guiding material so that the illuminated portion is continuously and brightly lit. There are symbols consisting of letters or numbers to indicate the functions controlled by the operation of the switch on the operation portion of the switch knob. In order to indicate the symbols, for example, an opaque plate in the shape of the symbol is insertion molded into the operation portion, or a transparent lens is insertion molded into the operation portion and the symbol is printed thereon.
However, in order to indicate the symbol on the operation portion of the switch knob, when an opaque plate is insertion molded into the shape of the symbol into the operation portion, as in the first method, there was a problem that the number of the parts that comprised the switch knob increased. In the latter method, when the symbol is printed on the operation portion, and the operation portion is operated by a finger over a long period of time, there is a problem that the printed symbol is abraded or peeled and eliminated. In addition, for the structure in which a cam system is located on the back side of the operation portion, the light on the indicator becomes inconsistent because the cam system becomes an obstacle.